Yes they are the slimline version. Good to know the standard size hold more beer. I brew quite a bit of smaller 2 and 3gal batches so I like small kegs for those.The slimline ones? I have heard that the slimline versions hold less than stated. I have several of the "2.5 gallon" standard ones, and they hold about 2.8 gallons up to the gas post and about 2.9 gallons right to the rim. The kegs themselves are marked "10L / 2.6 gallon."
Overall I am very happy with the small Torpedo kegs. I splurged on 2 of them at $80 each (now they are $110 at MoreBeer) and I got another 2 from a friend (along with a 3.5 gallon Ss Brewtech Brew Bucket). But while I love having the four small kegs, the current $440 price point would be very hard to justify.
I live close to morebeer and they have seasonal instore sales so I picked mine up a few years back at the lower price with a discount which made the cost more palatable. I bought my cannonballs from NB at a discount too during their sales.